Application and Optimization of hexavalent chromium (Cr(VI)) removal from aqueous solution using synthesized local termite mound with chicken eggshell adsorbent

Abstract

Water is a precious resource over the world and a universal solvent for most dissolved particles. On the other hand, the persistence of uncontrollable hexavalent chromium (Cr(VI)) hazards adversely affects life in the world in future generations due to it accounts for several disorders in plants and animals. Such trace ions are taken into consideration as a contaminant whilst their concentrations increase beyond their limit level that causing critical danger to the world. So, in order to avoid these heavy metal effluents from industrial wastewater adsorption is the best, versatile and efficient alternative. Also, it was observed that most of the adsorbents do have not sufficient usability as a result of they have low adsorption capacities with a long contact time, and inability to work at the natural pH of water. Therefore, it was imperatively developed to maximum removal efficiency of Cr(VI) found to be 99.79% at pH, adsorbents dosage, initial Cr(VI) concentration, and contact time were valued to 7pH, 6g/L, 40mg/L, and 75minutes respectively. This was done after the dried and size reduced termite mound-eggshell powder 1:1 mass ratio mixture was thermally transformed at 850℃ by using a muffle furnace and the experimental data generated using adsorbent of adsorption with the help of UV-vis spectrophotometry. Extensively, the samples were characterized like its proximate analysis, particle size, surface charge, functional groups, and adsorption isotherm and kinetics models and optimized by using design expert software besides investigating competitiveness of other heavy metals that fit the active site of termite mound-eggshell adsorbent. Based on these Freundlich isotherm as well as pseudo-second-order kinetic models provided a good description of adsorption that fitted well to concerning R 2 value of correlation data. The ANOVA was performed using CCD of quadratic model and its regression coefficient becomes 0.9986 which is favorable as closer to one. The optimum model predictions of 98.96% were in good agreement with a conducted experimental data generated 95.15% output. Extensively, during the study of regeneration adsorbent, desorption was successfully achieved with greater than 85% Cr(VI) ions removal efficiency by using 1.0MNaOH treatment. So, these results show that a mixture of synthesized adsorbents is a better promising for Cr(VI) ions adsorption